Object location and reporting system for harsh RF environments

ABSTRACT

A system verifies torquing of pressure fittings in an aircraft wheel well. A strain gauge and an ultra-wide band (UWB) pulse signal generator are placed on a wrench used to torque the fittings. The strain senses the torque applied by the wrench, and the pulse signal generator generates UWB pulse signals indicating the location of the fitting and the torque applied to the fitting. The pulse signals are received by UWB radios within the wheel well, which generate location measurements based on the received pulse signals. A processor automatically calculates the location of the fitting being torqued based on the location measurements, and a display produces a 3-dimensional image of the fittings and their torque status.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser.Nos. 12/145,623, and 12/145,637 both filed concurrently herewith on Jun.25, 2008, each of which applications is incorporated by reference hereinin its entirety.

TECHNICAL FIELD

This disclosure generally relates to object location systems, and dealsmore particularly with a system for locating, monitoring and/orreporting a condition of the object within a harsh RF environment.

BACKGROUND

During the production of complex assemblies, such as aircraft, there issometimes a need to monitor assembly operations and verify that certainoperations have been properly performed on a subassembly. For example,aircraft landing gear may be controlled by one or more hydraulic systemscomprising hundreds of hydraulic tubes and fittings that must beassembled within a relatively small wheel well. Each of these fittingsincludes a nut that is tightened or “torqued” by an assembly worker to anominal torque value. Because of the large number of nuts that must betorqued, it is desirable to monitor and verify that all of the nuts havebeen properly torqued, since the failure to properly assemble fittings,and/or torque nuts to nominal values may result in hydraulic leaks thatmust be later corrected. Past attempts to verify that nuts have beenproperly torqued have been limited to the application of marks on thenuts in order to visually indicate that they have been torqued, howeverthis technique may be subject to human error, and in any event, may notallow verification that the nut has been torqued to the correct value.

A variety of techniques have been developed for locating and monitoringobjects such as parts and subassemblies in three dimensional space,including those utilizing radio frequency (RF), optic, sonic andchemical communication, however, each has limitations in terms ofaccuracy and effectiveness within harsh communications environments. Forexample, known object location systems may be ineffective in thoseenvironments where line-of-sight (LOS) to the object is not available,or where structures or surfaces within the environment result in signalreflection and/or attenuation.

Known object location systems may not be well suited for monitoring theproper assembly of the hydraulic tube fittings, because these locatingsystems may not be capable of either locating the nuts, or locating thenuts with sufficient accuracy to distinguish between closely spaced nutswithin a highly confined, crowed environment such as a wheel well.Moreover, the use of RF techniques to monitor nut torquing isparticularly challenging due to the adverse effects of multipath causedby the abundance of metallic objects in a wheel well environment, andthe complex physical layout of the wheel well which lacks fixedpositioning system infrastructure.

Accordingly, there is a need for a system for locating and reporting thecondition of objects within a harsh RF environment such as a wheel wellin an aircraft.

SUMMARY

The disclosed embodiments provide a system for locating and monitoringobjects in harsh RF environments and for reporting at least onecondition of the object. The system may be used, for example, inmonitoring and verifying that certain operations have been performed oncomponents or subassemblies during the production of complex assemblies,such as aircraft. One advantage of the disclosed system resides in itsability to detect the position of an object with a high degree ofprecision, even in harsh RF environments having an abundance of metalparts and lacking fixed infrastructure. In addition to locating objects,the system may transmit data representing a condition, such as a torquevalue in applications where the system is used to monitor torquing ofnuts within a wheel well of an aircraft. The disclosed embodimentsfurther include a reporting and display system that provides an image ofthe located object within a three dimensional display of its surroundingenvironment, as well as a display of acquired data relating to thecondition of the object.

Robust location monitoring in harsh RF environments is achieved throughthe use of low power ultra-wideband (UWB) based techniques that minimizethe effects of signal reflection, signal attenuation and lack of LOS inthe harsh RF environment. The disclosed embodiments advantageouslyutilize signal processing and receivers that maintain required accuracyfor robust operation in those situations where the LOS from atransmitter to one of the receivers is blocked. This is achieved byinstalling extra receivers above the minimum required for performingtime delay of arrival (TDOA) processing and then performing signalprocessing to identify the receiver that is not in LOS with respect tothe transmitter.

In one application, the disclosed embodiments may be useful insupporting a knowledge-based manufacturing control system providing realtime information that may be advantageously used in assembly processessuch as those used in the aircraft industry. The system allows assemblyworkers and quality control personnel to quickly and easily identifywhich assembly tasks have been completed and which not have yet beencompleted, along with quantitative data indicating whether the assemblyoperations satisfy nominal specifications.

According to one disclosed embodiment, a system is provided for locatingand reporting at least one condition of each of a plurality of objectswithin a harsh RF environment. The system comprises: a portable,ultra-wideband (UWB) pulse signal generator moveable to the location ofeach of the objects and operative for transmitting UWB pulse signalsreporting a condition of the object at the location; a group of UWBradios within the harsh RF environment for receiving the transmitted UWBpulse signals from the pulse signal generator and for generatingmeasurements related to the position of the pulse signal generator basedon the received UWB pulse signal; a processor for calculating the threedimensional position of the pulse signal generator using themeasurements generated by the UWB radios; and, a system for displayingan image of the object whose condition is being reported, and fordisplaying the reported condition of the object. The system may furthercomprise a tool for performing an operation on each of the objects,wherein the pulse signal generator is mounted on the tool, and thereported condition is related to the operation performed on the objectby the tool. The tool may comprise, for example and without limitation,a wrench and the object may comprise a threaded fitting.

According to another disclosed embodiment, a system is provided formonitoring the use of a tool used to complete an operation on each ofthe plurality of subassemblies in a harsh RF environment within anaircraft. The system comprises: means on the tool for sensing thecompletion of an operation on the subassembly; a UWB pulse signalgenerator coupled with the sensing means for transmitting UWB pulsesignals reporting the completion of the operation; a group of UWB radioswithin the aircraft for receiving the transmitted UWB pulse signals froma pulse signal generator, and for generating measurements related to theposition of the pulse signal generator; means coupled with the group ofUWB radios for calculating the three dimensional position of the toolusing the measurements generated by the UWB radio; and, display meansfor displaying an image of the subassembly on which the operation hasbeen completed by the tool. The tool may comprise a wrench, and thesensing means may comprise a strain gauge for sensing the torque appliedby the wrench to the subassembly. The display means may include a dataset file representing a three dimensional view of the plurality ofsubassemblies, and a display for displaying the three dimensional viewof the subassemblies as well as the status of the completion of anoperation on at least one of the subassemblies. The calculating meansmay include a data compilation program for compiling the measurements,and a processor for calculating the three dimensional position of thetool using the data compilation program. The system may further comprisea receiver for assembling the measurements generated by the UWB radiosand for transmitting the assembled measurements to the calculatingmeans.

According to a disclosed method embodiment, acquiring data relating toeach of a plurality of objects located within a harsh RF environmentcomprises: moving a sensor to the location of each of the objects;sensing data at the object; transmitting the sensed data from thelocation of the object using UWB pulse signals; receiving the UWB pulsesignals at multiple positions within the harsh environment; using thereceived UWB pulse signals to generate location measurements related tothe location of the object from which the sensed data was transmitted;using the location measurements to determine the location of the objectin a first coordinate system; and, displaying an image of the objectfrom which the sensed data was transmitted in a second coordinatesystem. The first coordinate system may be a coordinate system withinthe harsh RF environment, and display of the image of the object mayinclude displaying a three dimensional image of the objects in the harshRF environment from a graphics file wherein the second coordinate systemis in the three dimensional image of the objects. The method may furthercomprise placing the sensor on a tool and performing an operation on theobjects using the tool, wherein the sensed data relates to the operationperformed on the objects. The tool may comprise a wrench and the sensormay comprise a strain gauge. Generating the location measurements mayinclude measuring the angle of arrival and the time difference ofarrival of the pulse signals at each of the multiple locations.

According to a further method embodiment, monitoring a tool used tocomplete an operation on subassemblies in a harsh RF environment withinan aircraft, comprises: transmitting UWB pulse signals from the locationof the subassembly indicating an operation has been performed on thesubassembly; receiving the pulse signals at UWB radios within the harshenvironment; using the pulse signals to generate location measurementsrelated to the location of the subassembly from which the pulse signalsare transmitted; using the location measurements to determine thelocation of the subassembly from which the pulse signals are transmittedin a coordinate system of a harsh RF environment; and, displaying thesubassembly from which the pulse signals are transmitted within a threedimensional image of the harsh RF environment. The method may furthercomprise placing a UWB pulse signal generator on the tool fortransmitting the pulse signal; and using a sensor on the tool forsensing a condition indicating that the operation has been performed onthe subassembly. The method may also comprise placing the UWB radios inlocations within the harsh RF environment such that at least two of theUWB radios are within the LOS of each of the subassemblies.

The disclosed embodiments satisfy the need for a system and relatedmethod for locating objects within a harsh RF environment and forreporting at least one condition relating to the object.

Other features, benefits and advantages of the disclosed embodimentswill become apparent from the following description of embodiments, whenviewed in accordance with the attached drawings and appended claims.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is a block diagram of a system for locating objects in a harsh RFenvironment.

FIG. 2 is a perspective view of an aircraft, including a threedimensional coordinate system used to define the location of objectswithin the aircraft.

FIG. 3 is a perspective view showing a portion of a wheel well formingpart of the aircraft shown in FIG. 2.

FIG. 4 is a side view of a wrench used to torque nuts on the hydraulicfittings shown in FIG. 3.

FIG. 5 is a combined block and diagrammatic illustration of a system forlocating and reporting the condition of objects within a harsh RFenvironment.

FIG. 6 is a simplified flow diagram of a method for determining thethree dimensional position of the pulse signal generator shown in FIG.5.

FIG. 7 is a diagrammatic illustration showing the major components ofthe locating and reporting system.

FIG. 8 is a typical screen display showing a monitored object and areported condition.

FIG. 9 is another screen display showing summary information related tothe monitored objects and reported conditions.

FIG. 10 is a simplified flow diagram illustrating a method for locatingand reporting the condition of objects in harsh RF environments.

FIG. 11 is a flow diagram of aircraft production and servicemethodology.

FIG. 12 is a block diagram of an aircraft.

DETAILED DESCRIPTION

Referring first to FIG. 1, the disclosed embodiments broadly relate to asystem generally indicated by the numeral 20 for locating each of aplurality of objects 22 positioned within a harsh RF environment 24, andfor reporting at least one condition related to the located object 22.The three dimensional location of each of the objects 22 may be definedin a three dimensional coordinate system 26 within the harsh RFenvironment 24. As used herein, “harsh RF environment” is intended tomean environments in which obstructions or other environmental factorsresult in RF signal reflection, signal attenuation and/or signalblockage due to the lack of LOS between transmitter and receiver.

The locating and reporting system 20 may include a UWB pulse signallocating system 28 within the harsh RF environment 24, and a monitoring,display and reporting system 30 which monitors the location of theobjects 22 within the coordinate system 26 and displays these objectsand reported condition within a second, later discussed coordinatesystem. As will be discussed below in more detail, the system 20 may beused to locate each of the objects 22 directly or indirectly by locatinga portable component such as a tool which is moved to the location ofeach of the objects 22.

UWB location monitoring is advantageous in many applications because ofthe ability of UWB signals to penetrate walls and other solid objectswhile maintaining resistance to multipath (or Raleigh) fading. Moreover,UWB location monitoring may possess interoperability with other radiofrequency based communication systems. Although UWB signals may be ableto penetrate most solid objects, these signals may be reflected off ofmetallic objects, creating multipath effects unless an appropriatetransmission protocol is selected.

Referring to FIG. 2, the locating and reporting system 20 may be used tolocate objects 22 on an aircraft 32 in which object space may be definedin a three dimensional coordinate system 26 of the aircraft 32. Theobject 22 may comprise, without limitation, subassemblies (not shown)upon which operations are performed during the production and assemblyof the aircraft 32. For example, as shown in FIG. 3, a wheel well 36 onthe aircraft 32 may contain a multiplicity of hydraulic tubes 40 havingthreaded fittings 41 provided with nuts 38 for connecting and tighteningthe fittings 41. The wheel well 36 may include various metallicstructures 42 used for reinforcement or component mounting that precludeLOS within the wheel well 36 and/or reflect or attenuate RF signals. Insome cases, the nuts 38 may be located in close quarters to which theremay be limited access, as where they are tightly grouped, for example,against a bulkhead 43.

Reference is now made to FIGS. 4-7 which depict additional details ofthe locating and reporting system 20 adapted for use in locating andreporting the torque condition of the nuts 38. In this application, asbest seen in FIG. 5, the system 20 utilizes a UWB pulse signal locatingsystem 28 which comprises a UWB pulse signal generator 52 carried on anelectronic wrench 44, and a plurality of UWB radios 60 that areoptimally positioned within the wheel well 36 such that at least two ofthe UWB radios 60 are within the LOS of each of the nuts 38.

As shown in FIG. 4, the electronically monitored torque wrench 44 usedto torque the nuts 38 includes a head 45 mounted on the end of a handle46. The head 45 includes jaws 48 for engaging the flats of the nuts 38,and a strain gauge sensor 50 mounted near the jaws 48. The strain gaugesensor 50 produces an electrical signal related to the magnitude of thetorque applied to a nut 38 by the wrench 44.

The UWB pulse signal generator 52 is contained within the handle 46 andtransmits UWB pulse signals on an antenna 56 carried on or within thehandle 46. The UWB pulse signals generated by the UWB pulse signalgenerator 52 may include data representing the magnitude of torquesensed by the strain gauge 50. Although not shown in the drawings, thewrench 44 may include a measuring and triggering circuit which measuresthe amount of torque sensed by the strain gauge 50 and triggers thepulse signal generator 52 to transmit signals when a threshold torquevalue has been sensed, representing, for example and without limitation,a nominal torque value for the nuts 38. An indicator light 58, which maycomprise for example, without limitation, an LED, is mounted on the head45. The indicator light 58 is operated by the measuring and triggeringcircuit to provide the assembly worker with a visual indication when thenominal torque value has been reached. The pulse signal generator 52 aswell as the light 58 and related measuring and triggering circuit may bepowered by a battery 54 housed within the handle 46 of the wrench 44.

Aircraft wheel well applications typically may lack infrastructure thatcould otherwise provide references useful in making locationmeasurements. Accordingly, the nodes, i.e. radios 60 may be deployed atpositions that optimize LOS communication with the locations where thenuts 38 are to be torqued. The common coordinate system 26 establishedwithin the wheel well 36 allows estimations of locations within a commonframe of reference. It may also be desirable to optimize thetransmission protocol in order to reject reflective signals by usingtiming techniques carried in the leading edge of the transmitted, UWBpulse signals.

According to one embodiment, the generated pulse signals may be basebandsignals that are mixed by a mixer to move their center frequency to thedesired frequency bands which may be, in an application involvingmonitoring of nut torquing within a wheel well 36, around 4 GHz,providing an effective spectrum of approximately 3.1 to 5.1 GHz, andlocation measurement accuracy less than approximately one-half inch. Inother applications, a UWB pulse signal generator 52 having a centerfrequency of approximate 6.85 GHz for a full FCC part 15 spectrum spreadof 3.1-10.6 GHz, may be appropriate.

In accordance with the disclosed embodiments, the deployment of ad hocnodes in the form of the radios 60 can be used to navigate around anyblockages in the LOS between the location of the pulse signal generator52 and the radios 60. Various reference materials exist in the art whichteach suitable methods and techniques for resolving positional estimatesin a network of ad hoc nodes including, for example and withoutlimitation the following:

-   “Robust Header Compression WG”, URL:    http://www3.ietf.org/proceedings/04nov/slides/rohc-0.pdf-   Perkins, C., “Ad hoc On-Demand Distance Vector (AODV) Routing”,    Network Working Group, RFC 3561, July 2003.-   Agarwal, A. and S. Das, “Dead Reckoning in Mobile Ad-Hoc Networks”,    IEEE WCNC 2003, the 2003 IEEE Wireless Communications and Networking    Conference, March 2003.-   Thales, Research & Technology Ltd. “Indoor Positioning”, URL:    http://www.thalesresearch.com/Default.aspx?tabid=166

Some of the techniques disclosed in the reference material cited aboveuse iterative lateration of the generated pulse signals by solving aconstraint based positional model. While this approach may besatisfactory for some applications, in other applications, such aslocating nuts within an aircraft wheel well it may be necessary that thead hoc network be propagated with position aware nodes in order toprovide the desired results.

As will be discussed below in more detail, the UWB radios 60 receive thepulse signals from the wrench 44 and generate location measurements thatmay be used to calculate the location of the wrench 44, and thus, thelocation of the nut 38 being torqued by the wrench 44. In otherembodiments, it may be possible to use one or more UWB radios 60 b whichinclude a pair of spaced apart receiving antennas 60 c, 60 d. The UWBradio 60 b generates location measurements based on the angle of arrival(AOA) and the time difference of arrival (TDOA) of the pulse signals 76transmitted by the pulse signal generator 52 on the wrench 44. In thecase of the UWB radio 60 b, the pulse signals 76 arrive respectively atthe two antennas 60 c, 60 d at slightly different angles θ₁ and θ₂relative to a reference axis 80 that is based in the coordinate system26 (FIGS. 1 and 2) used to locate the nuts 38 in the three dimensionalobject space. Similarly, UWB radios 60 each measure the AOA and TDOA ofthe arriving pulse signals 76 relative to the reference axis 80. The AOAand TDOA measurements generated by at least two of the radios 60 maythen be used to calculate the three dimensional location of the pulsesignal generator 52 (and thus the wrench 44 and nut 38) using commoniterative lateralization techniques.

Any of several different techniques may be employed for measuring theAOA positioning. One such method has been previously described in whichthe UWB radio 60 b includes two spaced apart receiving antennas 60 c, 60d each of which receives the signal transmitted by the pulse signalgenerator 52. The angle of the line connecting the radio 60 and thetorque wrench 44 is measured with respect to source data stored in the3D data set files 72. This reference angle corresponds to theorientation of the line intersecting each of the collocated antennas 60c, 60 d. By measuring orientation to multiple reference antennas, theposition of the torque wrench 44 may be determined.

Various techniques can be used for measuring TDOA. One such methodinvolves receiving the transmitted pulse signals by multiple UWB radios60 and dedicating one of the receiving radios 60 a to calibrating theremaining radios 60 in the network. The receiving radio 60 determinesthe direct path to the intended torque wrench 44 by measuring the TDOAof the signal. At least four such measurements may be required todetermine the position of the torque wrench 44 by interative lateration.

The performance of the radios 60 may be measured in terms of the packetsuccess rate, accuracy of measured vs. actual distance, standarddeviation and the signal/noise levels. The packet success rate may bedefined as the number of successful packet exchanges between the radios60. The measured distance is computed by processing the UWB pulsesignals transmitted by the pulse signal generator 52. The actualdistance is the distance between two receiving radios 60 as measuredusing a physical device. The standard deviation is a measure of howwidely the measured distance values are dispersed from the mean. Thesignal and noise levels may be computed from the signal waveform asfollows:

${SignalLevel} = {10*{\log( \frac{SquareofMaxValueofADCCounts}{2} )}}$NoiseLevel = 10 * log (NoiseVarianceof 5 nsOfTheWaveform)

The system 28 may include a UWB reference radio 60 a which broadcasts abeacon signal 65 that is used to calibrate the UWB radios 60. Because ofthe close quarters and various obstructions such as structure 42 thatmay be present within the wheel well 36, one or more of the UWB radios,such as UWB radio 60 c may not be within the LOS of the pulse signalgenerator 52. The required accuracy or location measurement where theLOS between the transmitter 52 and one of the radios 60 is blocked canbe overcome by installing extra radios 60 over the minimum numberrequired for normal TDOA calculations, and then performing signalprocessing algorithms to identify the particular receiver that is notwithin LOS with the pulse signal generator 52.

The location measurements generated by the UWB radios 60 may betransmitted from the system 28 to a UWB receiver and data assembler 62which assembles the location measurements, along with the torque dataforming part of the pulse signals transmitted from the wrench 44.Depending upon the application, the assembled data may be transmittedthrough a network 64 to the monitoring, display and reporting system 30.The networks 54 may comprise, for example and without limitation, a WAN,LAN or the Internet. The monitoring, display and reporting system 30 mayinclude a processor 68, data compilation program 68, data displayprogram 70, three dimensional data set files 72 and one or moredisplays, such as the display 74 and a portable display 75.

The processor 66 may comprise a programmed PC which uses the compilationprogram 68 to calculate the position of the pulse signal generator 52based on the location measurements. The processor 66 also uses thedisplay program 70 to cause the display of images which illustrate orhighlight the location of the nut 38 being torqued within a threedimensional image produced from the data set files 72. The threedimensional data set files 72 may comprise, for example and withoutlimitation, a CAD file produced by any of various solid modelingprograms such as, without limitation, CATIA. In effect, the system 30maps the locations of the nuts 38 to data set coordinates in the solidmodeling program.

The method for calculating the position of the pulse signal generator 52is illustrated in FIG. 6 in which the AOA and TDOA are respectivelymeasured at 80 and 84 by the UWB radios 60. In some cases, measurementbias may be introduced as a result of the lack of LOS between radios 60,and incorrect lock on the signal to detect direct path or leading edgeof the signal. This is due to the consistent leading edge detectionoccurring at the shortest path between the radios 60. This measurementbias may be compensated using any of several methods, including usingleading edge algorithms using look-up tables for regions within thewheel well 36 to compensate for the bias or for counting for the erroras position errors. Accordingly, compensation may be made at 86 for themeasurement bias. Finally, at 88, the processor 66 calculates the threedimensional position of the pulse signal generator 52 within thecoordinate system 26 of the harsh RF environment 24, which in theillustrated example, comprises the wheel well 36.

Referring now particularly to FIG. 7, the displays 74, 75 each combinegraphic and quantitative data in real time to provide a display of thecurrent state of the wheel well 36. In order to display the nut 38 beingtorqued in a three dimensional reference image assembled from the 3Ddata set files 72, the processor 66 mathematically translates the 3Dlocation of the pulse signal generator 52 in the coordinate system 26 ofwheel well 36, to a second coordinate system 34 of the 3D image createdfrom the data set files 72. The first coordinate system 26 effectivelydefines object space 35, i.e. the 3D space in which the wrench 44 ismoved from nut-to-nut 38, and the coordinate system 34 defines the imagespace 37 containing the displayed the image created from the 3D data setfiles 72.

The main display 74 may be used by production personnel to remotelylocate, monitor and record the completion of assembly operations, suchas the torquing of the nuts 38. Additionally, a portable display 75 maybe employed by an assembly worker to view the same or similar data thatis displayed on display 74 so that the worker can monitor and verifywhich of the nuts 38 have been torqued, or have yet to be torqued.

Reference is now made to FIG. 8 which discloses a typical screen display90 that may be viewed on either of the displays 74, 75. In this example,a hydraulic module 92 is displayed in which an arrow 96 is used toindicate a particular nut 94 that is or has just been torqued. Summaryinformation in a table 98 may also displayed which may indicate a modulenumber 100 identifying the module 92, a fitting number 102 identifyingthe particular fitting being torqued, the status 104 of torquecompletion and a final torque value 106.

Referring now also to FIG. 9, summary information may be displayed onthe display 74 that may include groups 110 of modules along with indicia112 that identifies the module group. Additionally, tables 114 may bedisplayed that show torque status in summary form. For example, thetorque status may include the number 116 of nuts that have been torquedfor a module group 110, and the number 118 of nuts that have not yetbeen torqued for each of the module group regions 120. A variety ofother types of specific of summary information may be displayed alongwith images of the modules and/or fittings, all in real time while anassembly worker is assembling the fittings and torquing the nuts 38.

Referring to FIG. 10, according to a method embodiment, torquing of thenuts 38 may be monitored, recorded and displayed. Beginning at 122, aproduction worker uses the electronic wrench 44 to torque a nut 38. Whenthe strain gauge 50 (FIG. 4) senses that the nominal torque value hasbeen reached, the wrench 44 transmits torque signals comprising UWBpulse signals that contain the torque value, shown at step 124. Thetorque signals (UWB pulse signals) are received at the UWB radios 60within the wheel well 36, as shown at 126. The resulting locationmeasurements are then used by the processor 66 to calculate the locationof the wrench 44 in three dimensional object space, as shown at 128. At130, the processor 66 associates the wrench location with a particularnut 38, and at 132, the torque value for the nut is recorded. At 134,the processor 66 translates the location of the nut from the coordinatesystem 26 of the wheel well 36, to the coordinate system 34 of the threedimensional space represented by the displayed image. The nut 38 is thendisplayed along with the recorded torque value at 134. Torqueverification reports may be optionally generated, as desired, at 136.

Embodiments of the disclosure may find use in a variety of potentialapplications, particularly in the transportation industry, including forexample, aerospace, marine and automotive applications. Thus, referringnow to FIGS. 11 and 12, embodiments of the disclosure may be used in thecontext of an aircraft manufacturing and service method 138 as shown inFIG. 11 and an aircraft 140 as shown in FIG. 12. During pre-production,exemplary method 138 may include specification and design 142 of theaircraft 140 and material procurement 144. During production, componentand subassembly manufacturing 146 and system integration 148 of theaircraft 140 takes place. Thereafter, the aircraft 140 may go throughcertification and delivery 150 in order to be placed in service 152.While in service by a customer, the aircraft 140 is scheduled forroutine maintenance and service 154 (which may also includemodification, reconfiguration, refurbishment, and so on).

Each of the processes of method 138 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 12, the aircraft 140 produced by exemplary method 138may include an airframe 156 with a plurality of systems 158 and aninterior 160. Examples of high-level systems 158 include one or more ofa propulsion system 162, an electrical system 164, a hydraulic system166, and an environmental system 168. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of thedisclosure may be applied to other industries, such as the marine andautomotive industries.

Systems and methods embodied herein may be employed during any one ormore of the stages of the production and service method 138. Forexample, components or subassemblies corresponding to production process146 may be fabricated or manufactured in a manner similar to componentsor subassemblies produced while the aircraft 140 is in service. Also,one or more apparatus embodiments, method embodiments, or a combinationthereof may be utilized during the production stages 146 and 148, forexample, by substantially expediting assembly of or reducing the cost ofan aircraft 140. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while the aircraft140 is in service, for example and without limitation, to maintenanceand service 140.

Although the embodiments of this disclosure have been described withrespect to certain exemplary embodiments, it is to be understood thatthe specific embodiments are for purposes of illustration and notlimitation, as other variations will occur to those of skill in the art.

1. A method of acquiring data relating to each of a plurality of objectslocated within a harsh radio frequency (RF) environment, comprising:moving a sensor to the location of each of the objects; sensing data atthe object; transmitting the sensed data from the location of the objectusing ultra-wideband (UWB) pulse signals; receiving the UWB pulsesignals at multiple positions within the harsh environment; using thereceived UWB pulse signals to generate location measurements related tothe location of the object from which the sensed data was transmitted;using the location measurements to determine the location of the objectin a first coordinate system; and, displaying an image of the objectfrom which the sensed data was transmitted in a second coordinate systemare processed/controlled by a processor.
 2. The method of claim 1,wherein: the first coordinate system is a coordinate system within theharsh RF environment, and displaying the image of the object includesdisplaying a 3-dimensional image of the objects in the harsh RFenvironment from a graphics file, and wherein the second coordinatesystem is in the 3-dimensional image of the objects.
 3. The method ofclaim 1, further comprising: placing the sensor on a tool; andperforming an operation on the objects using the tool, wherein thesensed data relates to the operation performed on the objects.
 4. Themethod of claim 3, wherein: the tool is a wrench, the sensor is a straingauge, and the sensed data relates to torque applied by to the object bythe wrench.
 5. The method of claim 3, wherein generating the locationmeasurements includes: measuring the angle of arrival and the timedifference of arrival of the pulse signals at each of the multiplelocations.
 6. The method of claim 3, wherein the pulse signals arereceived by UWB radios respectively positioned at the multiplelocations, and the method further comprises: compensating for bias inthe measurements resulting from the delivery of the pulsed signals toone of the UWB radios being blocked.